Lasang Pinoy 22, Rice to the Challenge: The Puto Experiments

Please note that I haven’t experimented with this recipe in a couple of years. The last one was 2010 and I didn’t bother documenting because it was a busy time in our lives. My routine when making puto these days is soak rice overnight, and then refrigerate for up to 3 days or until I have time to make it — I switched to this technique because my life is so unpredictable sometimes and I had an instance when I forgot the mixture for over a week and as you can imagine, I ended up with a really icky vomit-inducing mess. I wish I could experiment on this recipe again and answer all the questions here, but as it is, I don’t have time right now. Please feel free to keep on commenting and sharing your experiences via the comment section. I’ll join in when I can. Thanks for your understanding and good luck with your puto experiments!

Judging from the requests I get here, by e-mail, from friends, etc., making Philippine puto is one of the biggest mysteries of our cuisine. Traditional recipes aren’t easy to find, and even people who used to make puto the old way seem to have resorted these days to the use of wheat flour. Even my aunt whom I was counting on to provide me with a reliable, old-fashioned recipe, recently sent me her “tried-and-true” wheat puto recipe. She said they simply don’t make it “that way” anymore. So it’s left largely up to us culinary enthusiasts to discover the secrets behind traditional puto making. My goal was not to duplicate any specific puto — the objective is simply to find a puto recipe that will work where I am with what I’ve got. After this, I’ll leave it up to you, dear readers, to try out and experiment and figure out other specifics to hopefully achieve puto that will make you and your loved ones happy.

My very first clue as to how puto was made in the old days was provided by Lewing Mendoza, a friend in St. Louis who makes wonderful puto from scratch. Her recipe which she gave to me back in 1995 became the basis of many experiments. It was a good recipe, and produces a serviceable puto, but I think that experience taught her a few tricks she didn’t reveal, because try as I might I couldn’t copy hers exactly. As with my many kitchen adventures though, the experimentation couldn’t be done consistently or regularly — family commitments, travel, etc. If you’re a regular reader you’ve read that here before, I’m sure. My most extensive trials were carried out in 2001, when I attempted several batches, utilizing a rice starter that was fed repeatedly — after several good to very good results, I let it die the 4th day after a refreshment. After that, everything was put on hold, except for an occasional trial.

Until November 2007 when my Cebuana friend Cynthia passed along a recipe in one of her cookbooks and asked that I make the puto to go with her dinuguan. It was definitely the right time to try again, as we were entering into Advent and I had planned a leisurely month of almost no school for the kids, and lots of reading and kitchen fun instead for all of us. Cynthia’s recipe is different from Lewing’s recipe in that it includes fermentation periods, albeit shorter than the fermentation periods I had gone up to in
past experiments. Luckily, I still had my notes from 2001 so I did some combining here, some tweaking there, and just went puto-crazy the whole month of December.

Fermented Foods

Fermented foods intended for consumption have been around for centuries. Most likely rice fermentation was a product of necessity — the lack of refrigeration in the old days. People needed to do something with their food to make it keep for longer periods of time. Fermentation allows ingredients or the dishes themselves to develop microorganisms that aid in preserving the food and keep it from spoiling.

Rice starters are the result of fermentation. They are not just used for making puto , however. Many other countries use fermented cake-like preparations (some using rice, others different grains): the Korean jeungpyon and kichudok, the Indonesian tape, the Sri Lankan hopper (appa), the Ethiopian injera and the Sudanese kisra are some examples. Another similar product is the Indian idli, the main difference between that and our puto being the legumes and spices, and sometimes buttermilk, added to idli. (1, 2)

These products have been developed empirically over generations to suit local conditions and the majority involve primarily a lactic acid fermentation, but a detailed understanding of their microbiology is still in its early stages. (2)

Fermented rice is an integral component of soy sauce and wine making. Moldy rice starters called qu in China have also been used to improve the flavor of meat or fish sauces.

The purpose of the preparation of the starter is to grow mold on the rice and/or wheat grains to produce various kinds of enzymes useful in the production of shao-hsing wine. The difference between rice starter and wheat starter is that there is more saccharifying amylase in the former and more protease in the latter. – Rice by Bor Shiun Luh

(Rice starters are also becoming more popular as the number of people that suffer from wheat and other allergies increase. On a celiac board I visited there was talk about a brown rice starter which is on my list of must-try’s, as brown rice is more nutritious than the white with which we grew up.)

[Disclaimer before we continue: Chemistry is not one of my strongest subjects. I am just summarizing here what I’ve read and trying to convey how *I* understood it. If you see any errors, please feel free to correct and clarify. My main goal is to get a general picture of how the science behind puto -making works.]

puto is basically a steamed cake, prepared from rice ground with water and allowed to ferment. It is this fermentation that causes the production of natural acids and gases and leavens the puto. This becomes the starter, which then is used either to make a first batch of puto , or to inoculate subsequent batches.

Studies of microorganism content after fermentation revealed the presence of the following: Lactic acid bacteria, the most predominant being the heterofermentative Leuconostoc mesenteroides, plus to a lesser degree, Saccharomyces cerevisiae, or baker’s yeast. These are the organisms responsible for the fermentation and leavening that produce the unique characteristics of puto. L. mesenteroides initiates the fermentation process. S. cerevisiae is a minor component until the final stage of the fermentation in which it can reach as much as 18% of the total population, resulting in a small amount of ethanol. The yeast together with L. mesenteroides may play an important role in leavening the batter. (4, 5)

[One chart also listed Streptococcus faecalis as one of the microorganisms, but a discussion of its presence and possible deleterious effects (it’s already present in our bodies, but can also cause disease) — would be difficult to cover in this post, so I won’t go there — but do note that I am duly concerned and will write about this again at a later date if I find out anything else. The research simply stated that it was only significant in acid development, although the following quote may explain why we don’t get sick from eating puto.]

Lactic acid bacteria are used in the food industry for several reasons. Their growth lowers both the carbohydrate content of the foods that they ferment, and the pH due to lactic acid production. It is this acidification process which is one of the most desirable side-effects of their growth. The pH may drop to as low as 4.0, low enough to inhibit the growth of most other microorganisms including the most common human pathogens, thus allowing these foods prolonged shelf life. The acidity also changes the texture of the foods due to precipitation of some proteins, and the biochemical conversions involved in growth enhance the flavor. The fermentation (and growth of the bacteria) is self-limiting due to the sensitivity of lactic acid bacteria to such acidic pH. (6)

The specific qualities of different kinds of puto are dependent on microflora that are already present in the milled rice, and the kind of rice used. Microorganisms can either be aerobic or anaerobic. That is, they either need oxygen to do what they’re going to do, or not. Lactic acid bacteria are mostly anaerobic. It was found that aerobic bacteria present at the beginning of the fermentations disappeared.

A thorough discussion of fermentation and beneficial yeasts can be found here.

Materials needed: non-reactive bowl for soaking rice; fine-holed colander for draining, or a large strainer; blender; large piece of muslin or clean kitchen towel

Wash the rice twice, draining both times, then add the 4 cups of water and soak for 24-48 hours, but at the very least 8 hours.

Working with 3/4 of the soaked rice:

Drain, reserving the soaking water and putting it back in with the rest of the rice. Run through a blender with just enough of the soaking water to keep the machine moving. Wrap in muslin and drain for 24 hours, hung from a post or kitchen cabinet knob, with a bowl underneath to catch any drips.

Let the remaining rice sit for 18 more hours in the soaking water, covered with a clean kitchen cloth (don’t let the cloth touch the rice or the water). After 18 hours, drain, reserving the water. Run through the blender along with 2 tablespoons of day-old cooked rice, 2 tablespoons sugar, plus the soaking water, just enough for the mixture to keep moving in the blender. You will have a very thick batter. Let this mixture sit 6 more hours, covered with a clean kitchen cloth or piece of muslin.

Combine the two portions and add more of the soaking water to make a thickish batter. Let the whole thing ferment 5-9 more hours. If the timing on this is somewhat random it’s because my own timing wasn’t exact — there were days when I wasn’t too busy and could tend to the puto experimentation at the appointed time, other days I had to wait ’til kids were done with schoolwork or after dinner to work on it — but all of those that were tested between 5 to 9 hours turned out fine — sorry, I don’t have any data on <5 hrs or >9. Please feel free to experiment and share your results.

Add 3/4 cup sugar (or so, adjust to taste after you’ve made your first few batches) and 1/4 teaspoon salt.

At this point, you can start making the puto. OR, ferment for 4-5 hours more. You should see a definite change in volume here. Here’s also where I noticed a bigger difference in taste (perhaps because of the additional sugar which was allowed to ferment along with the rice).

When you are ready to make puto, I suggest you steam a small amount in a greased puto mold for 15 minutes over medium heat. Evaluate how the mixture rises, how sweet it is, if you need to balance out the flavors by adding a bit more salt, etc. If you think the puto would benefit from some baking powder, add up to 1 tablespoon, depending on how well the fermentation worked, i.e., how much the natural leavening has been developed. You may not need any AT ALL.

To make puto, pour into greased puto molds and steam over medium to medium-high heat for roughly 25 minutes. (I used bigger molds holding about 1/4 to 1/3 cup batter each.) The water should be kept at a nice, even, strong simmer if you want clean-looking puto with no cracks. I haven’t mastered this yet though I’ve played with different steaming configurations (e.g., bamboo on pot, stainless steel skillet with rack, cast iron skillet with rack and a plate, lining with muslin, lining with cheesecloth, etc.). I figured this part of the process was secondary — once I came up with the recipe that was closest to my personal ideal the rest would fall into place eventually. One no-no that I found using the cast iron skillet and a large bamboo 2-layer steamer basket: it’s very difficult to judge how strongly or weakly that water is boiling/simmering, so I had to adjust several times and made lots of annoying mistakes, like the puto not cooking enough, or just the top remaining uncooked, even after 25 minutes. Or REALLY big cracks and condensation forming IN the cracks, etc. Argh. What would probably work best, if you wanted to use a cast iron skillet, is to observe and wait until the water is steadily simmering before the actual steaming begins. My best results came from 1 layer of 6-7 puto at a time, on a rack, in a stainless steel skillet, with cheesecloth gently placed on top after the first 10 minutes of cooking.

If you want to try feeding and refreshing your starter, hold back 1/2 – 1 cup of the mixture prior to adding baking powder. Use it to start your next batch of puto. It has been found that 30% of the microflora in such recycled starters are yeast. Therefore you may notice that your fermentation periods are shortened by several hours. (I still have an 18-day-old starter in the fridge — which I forgot — that I’ll use in the next few days. I’ll post a pic — a nice crust has formed on top and the stuff inside seems to have been untouched by any foreign substances; it’s a bit bubbly, and (excuse me) saliva-y, for want of a better descriptor.)

As the fermentation progresses, you will notice that there’s a sour smell that develops, maybe even a bit alcoholic, but the mixture should not have any greenish or pinkish mold on it. If it does, do yourself a favor and throw it away — unless you’re a scientist and you know what you’re doing. I’m fairly adventurous about food but a possibly harmful mold that could trigger eczema, or worse, food poisoning, would automatically go into the dump. Experimentation is perfectly fine as long as you don’t let things get out of hand:) As for that sour smell you get from the fermentation — it will disappear as you cook the puto , leaving behind a nice aroma and character.

Comparative studies have been done by Tongananta (1971) and Sanchez (1975) (both studies cited in Handbook of Indigenous Fermented Foods by Keith Steinkraus) that may give you ideas on what variety of rice to use for your own experiments. For our purposes here, suffice to say that their charts showed that intermediate-high (but not too high) amylose content correlated with acceptability, volume, texture and flavor in the final product. I used Thai jasmine rice in mine, which is widely available in the US and has intermediate-to-high amylose content. They tested C-4, Intan, Wagwag, and IR varieties (of these, it seems C4 plus two IR varieties came out tops), but I wouldn’t know which ones are now available in the Philippines, so if you’re there, please try out what you think is best and let us know how you did.

ETA 07 Jan 2008: I mentioned Philippine varieties but I realize most of us trying to do this are outside the country. Not all Thai jasmine rices will work the same. I had best results with brands that cooked up dryer than others, i.e., in December I tried Elephant God, White Dove and Ba Con Nai. The White Dove worked best, followed by Elephant God. Ba Con Nai absorbed too much water and cooked up much gummier than the other two. Bearing this in mind my next combination will be a very dry long grain AND Jasmine for fragrance.

Add 2 egg yolks or 1 whole egg — closer to Binan puto but not quite there yet. I suspect they add food coloring to achieve that kind of yellow!

Use a wheat sourdough starter — not traditional, but I was quite pleased with the results — If you don’t consider yourself a purist or don’t mind wheat-based puto, this might be useful for you. However, I hesitate to recommend it because I grew my own sourdough starter from wild yeast (it’s been bubbling away for a year now) and so your results may differ from mine depending on where you are, how you made your starter, etc. If you’re interested, lmk and I’ll detail a recipe using my starter. You can also click on “Sourdough” under Categories to see some of my starter pics

Tried a shortened version — minimal ferment periods, about 4-6 hours each — using idli rava — an Indian product. I had bought a package more than a year ago, for an Indian recipe, then last summer I ran into an Indian friend and asked her what else I could do with it — she was the one who suggested I use it for Filipino rice cakes! Well, duh. It was very good, although I still liked my Jasmine puto better — but maybe with more experimentation… I should call her and ask her if the rice used for idli rava is aged — that might make a difference.

The recipe I got from Cynthia also uses coconut milk instead of water, and this makes a very yummy puto, despite the fact that I’ve had disasters in the past with coconut milk in puto — they come out too much like sapin-sapin! Her ratios are spot on though, using only 1/2 cup thick coconut milk in place of 1/2 cup soaking water. It changes the consistency a bit but the creaminess is rather nice and welcome.

Other suggestions for your own experiments, or things I’d like to try in 2008:

Using parboiled rice. Parboiling is a process which restores some of the nutrients lost through milling. I don’t like parboiled rice personally, but it may work for puto , who knows.

Use ragi as a starter. I’m thinking ragi may be similar to our Filipino bubud/bubod though the mold/yeast in it is different from those found in puto preparations. Ragi is available here.

Try storing Jasmine rice for a year and see how it works after storage.

Old rice is more flaky than freshly harvested rice. This difference may be due to (1) changes in the colloidal state of the starch from sol to gel and (2) the reduction in amylase activities in the grain (IRRI, 1996). [snip] Solutions of amylose and starch isolated from fresh rice have a slightly higher specific viscosity than the corresponding constituents from old rice. The water uptake capacity of fresh rice is greater than that of stored rice. – Handbook of Indigenous Fermented Foods by Keith Steinkraus

Try Chinese preparations using commercial yeast (they don’t have the same lengthy fermentation periods as our traditional puto , but my kids love them anyway, and I might learn a thing or two by trying them out.

Find a wine (or a beer) to experiment with — I was looking for a tuba or lambanog substitute, but no such luck. The closest I found was a pineapple-coconut cocktail, which may be useful, as sourdough fans have discovered the wonders of pineapple juice for our starters. Maybe it will work wonders on rice starter as well.

Try an idli recipe, or a puto-idli marriage; Filipino researchers have looked into this to enrich our puto with extra protein by adding beans. Hey, any food that can be made healthier is a winner for me!

Try adding 1 teaspoon lye prior to the last fermentation period — found this in a recipe which I haven’t tried.

I’d also play with the fermentation periods — please note that I was testing this, in winter, in Ohio — we had some 20-30 degree days AND some 50-60 days in December — Cincinnati is known for its crazy weather. Our thermostat is set to 68-70 during the day and 66(?) at night. However, there are some cold spots in the house, sometimes even the kitchen, esp. early in the morning, maybe because it’s just cold outside, or our insulation isn’t the best. At any rate, things like how warm your oven gets with the pilot light on (which I tried a couple of times) will also be a factor. Can’t wait to try this experiment in the summer, when it goes up to 90-100 degrees F here, more like Philippine weather.

Next Steps:

What I’d really like to see happen is for people to try out this experiment themselves, keep track of:

the variety of rice they used

periods of fermentation

temperature in their house

amount of water used (because this might be a function of the kind of rice you use)

if baking powder was indeed utilized, and

their satisfaction with the finished product.

I’ve tried in the past to get a yahoogroup going for this, to keep track of the variables listed above, but when it came down to subscriptions and committing to the survey, only a couple of people responded positively. My guess is that most people are not interested in experimenting and simply want a recipe they could try. Well, here it is. So I hope you do try it, and I hope you come back here and at least let us know how it went for you.

Other Issues

Probiotics

There have been quite a lot of talk about fermented foods being used as probiotics, in medical, homeopathic, and culinary circles. This is highly interesting for me because of allergies in the family and weak immune systems. For those of you interested in this, the following link may be helpful, from the NIH. I don’t think the LAB specific to puto have been classified as probiotic, but perhaps puto variations, e.g., brown rice or those with added ingredients might be an avenue to explore.

GMOs

In Genetics of Lactic Acid Bacteria there were some references to studying the risks associated with rice of transgenic origin. However, the book really wasn’t meant for the layman so I’ll see if our doctor/homeopath friends can do some “translating” for us. GMO foods are a big concern in our family so I’ll be watching this closely and let you know if I find anything relevant. One of the ways we’ve tried to change our diet is by switching to half-organic-brown-rice with our meals. Organic Jasmine rice is accessible to us, but at about 3x the price of regular Jasmine rice, and this is at our co-op where things are discounted heavily compared to the big dealers or supermarkets. Right now I’m thinking organic jasmine rice, aged for a year…. would make great puto…. but you’ll have to wait another year to see my results.

Additional Reading

This list is for the interested reader as well as for me. Some of these items are already available online, some are not, some may be borrowed through ILL; I’m trying to get a couple of articles from my tita who’s worked a long time at UPLB.

This edition of Lasang Pinoy, the Blogging Event, was hosted by JMom of Cooked from the Heart. Please be sure to visit her blog to see the roundup and visit the other participants! Thanks so much for hosting, JMom!! Hanggang sa muli! Sorry late, hee… There *are* pictures, I just need to edit them and upload and edit the post, etc., etc. They’re not the best though, as I didn’t really take the time to document every step — what with the holiday prep and all…

35 Comments

Beth Loggins
on 1 January 2008 at 21:57

Great post. Your puto quest is much appreciated. Just wondering if you have any pics of your finished puto?

Hi steff! i have renamed my blog to Saint Therese’s Roses. the adress is still the same, but the blog name is different. if you wouldn’t mind, could you name my link on your side bar to Saint Therese’s Roses? thanks steff! God bless you!

I’m just one of your many readers who wrote & requested for this puto making process & recipe from you so I would like to extend my appreciation to you for devoting your time during the busy holiday season to do this puto experiment. Your post is very informative. Thanks for sharing this, I will try to make puto again with your recipe & tips asap! Hopefully we can all master it & pass it on to the next generation so it will not get lost & be forgotten! Thanks again and Happy New Year to you & to your family!

As good as a thesis, Stef. The simplest is the hardest, as many cooks say. I’ve been on a puto recipe quest myself, and I haven’t been happy with what I’ve got so far. The ultimate recipe for me is the one for my beloved Calasiao puto – sadly, it is a best-kept secret.

you really did a great effort on your puto quest!!! I love puto with dinuguan! If we are having lechon, then there is dinuguan, the following morning should be puto and dinuguan! but I just buy the puto. Even my french hubby loves it too!

I agree with Kai on “as good as a thesis” . . . I knew that something really good was cooking in your kitchen when you replied to JMom’s reminder about the event . . . I should try out this puto recipe of yours! Great entry, Stef! Thanks!

Hi Stef,thank u very much for all the puto recipes.It is interesting to know that there are so many ways on how to ferment it.You have mentioned about “Ragi”,I would like to find out if you know where I could purchase Ragi.I don’t know any store here in Canada that sells Ragi.I will continue to experiment different ways on how to cook puto,and I will update you with the outcome.

Thanks for the comments, everyone! If you are trying this out, please make sure you see my “ETA” above (1/7/08) about Thai jasmine rice.

Beth, yes, I have pics as I mentioned, just haven’t had time to sit down and edit and post. Within the week, I hope!

Marilena, no problem!

Sr. Mary Martha, I’m pleasantly surprised and honored that you should drop by. Happy New Year to you and the sisters!

Lani, the link with the “ragi” would probably ship it to wherever you are (hopefully won’t be a problem with customs). Let me know if it is and I’ll see if there’s something we can do from here.
JMom, I really hope you try the bubud equivalent — would love to see your notes and thoughts on that!

hi stef!
happy new year too! i might not have time to read your entry verbatim but i definitely know where to go to in the event i need a detailed write up on puto! great job! and this is another fave of the kids…poo-tuh! not poo-tow this time! lol!

hello . thank you for the puto recipe. i started it last thursday, i cooked a sample batch on the designated date following your instruction. however, it did not rise and did not have a fermented taste to it. i gave it another day, by that time the puto dough had doubled in size. this time it was a success. it had the exact taste that i could remember. i made my 3rd sampling this evening. the dough is definitely bubbling at this time. i haven’t tasted it yet because i want it to rest overnight. otherwise it would be very sticky. i made another batch tonight using the remaining 1 cup fermented dough to 2 cups galapong. thanks again.—maria

Thank you for the very informative formulation of puto. I am also on a quest for a recipe of the putong binan. I tried one with the buterscotch mix but I was not happy with the results. It’s good I came across yours so I will be doing some experimentation

if you want to make puto binan maybe you should use brown sugar, no egg and some butter. I have been told that puto makers in binan soaked the rice overnight and then milled them. they are then spread over bilaos covered with cloth and allowed to dry overnight before it is again ……

i was looking for a rice puto recipe to compare the recipe my in-laws used to produce in the past as a business in iriga city that sent the children to school(no one among the children inherited the business, that’s why i got interested because the implements they used before are in our bodega including an old stone grinder they call ‘metate’). the ingredients consist of rice flour, muscovado, food color, baking powder, and the identity the Hermosos put to it to make it different from the rest was “kiniskis na buka” making rice puto softer and flavorful. my husband tells me that when he was still a kid, he and his older brother would help Itay (his grandpa) spend several hours making the puto and that was all the ingredients he could remember. i got to taste this “rice puto with buka” the first time my husband invited me to iriga fiesta. that time, Itay was still alive. anyway, with the info i got from you, i guess its time to bring out that ‘metate’ from our bodega and relive the puto Itay had made a living.

I tried to use the rice starter to make puto following all of the instruction, but the puto did not rise so I tried to add two teaspoons of baking powder for every cup of ground and fermented mixture.the result was satisfactory,it was very white and very light although a bit sour in smell and taste. My sis ask me what is that-smelly thing, like a cats bla ,bla you know..! I just told her it’s the fermented rice that i am experementing with to make a native style puto. Am I right? By the way,how can I reduce that kind of smell on the puto product.Okey na sana ang lasa pati kulay kaso nga lang e amoy pa rin yung asim. thanks again.

thank you for this article. I am currently experimenting with rice flour starter to make puto and you mentioned that your family has allergies/eczema made better with probiotics. My son is allergic to eggs, wheat and dairy and traditional puto is a great treat for him… we found some at a store near my in-laws’ and he ate the whole package in the car, it didn’t even survive until we got home! I’m also looking into this as a possible bread substitute for sandwiches, as he is going into 2nd grade would dearly love to have something like his friends’ packed lunches instead of rice and ulam all the time.

hi stef,
thanks for your recipe and experiment. like you, i experimented on different recipes posted on line and from cook books but never been satisfied with the results. i want the authentic rice puto, fluffy and springs back when touched. i will try your recipe and will keep you posted with the results. let’s keep on experimenting…
dolly

The yaya of my first born taught me how to make puto with tuba. So every sunday morning before she takes the day off she would buy tuba (freshly gathered, so it would have actively growing yeast), prepare the coconut milk and galapong. We steamed the mixture with banana leaves underliner on a bamboo steamer (like they use for siopao). It has been “light years” since i had done that, but the memory of the taste still lingers to this day. Frankly I had forgotten the actual proportion but it should not be too difficult to recreate it given the right ingredients.
The Calasiao puto “secret” as told by one of the major suppliers of Calasiao puto in Metro Manila is his stone grinder. I would have wanted to do a microbiological study of it to understand the fermentation process that goes into such , but it was just a thought that never saw fruition.
I came upon this blog because I am researching also on puto making the artisanal way, no wheat flour involved.
Am glad many are interested in the complexity of this seemingly simple item.

Hi, so I was just wondering after experimenting. I found a recipe elsewhere and your recipe, and I allowed my rice to soak for exactly 48 hours. However, after that soak, the soaking liquid was thick somewhat slimy, and had a slight sour smell. Is it maybe because I substituted one whole tablespoon of the rice for malagkit maybe? I make Chinese puto all the time with rice flour, but this would be my first time soaking fresh rice. Hmmm.

great research!mine is not as detailed as yours but i also found jasmine rice to be great for puto. and instead of making a starter like what they use in clay jars, i just use instant bakers yeast and ferment for at least 3 hours. though I still can’t achieve that distinct sour smell and taste maybe it has something to do with certain type of yeast and bio-chemical process with acid and bacterias